Determining the immigration potential of plants colonizing disturbed environments: the case of milled peatlands in Quebec

Summary 1. As an aid for restoration projects, the relative potential for plants to immigrate to sites after severe disturbance was investigated and an index developed to determine their relative immigration potential. The goal was to establish baseline knowledge for the species pool in severely disturbed sites prior to restoration. The method was based on the identification of potential colonists, inventories of populations in surrounding vegetation and autecological information on their maximum fecundity and dispersal by wind, water or animals. 2. The method was applied to milled peatlands in south-eastern Quebec, Canada, after the cessation of peat extraction activities. Thirty-two species, ranging from mosses to trees, which are common in natural or abandoned milled peatlands in southern Quebec, were selected as potential colonists. 3. Populations of study species differed markedly in edges of milled peatlands in terms of their abundance, presence and presence of fertile plants. An edge effect was apparent where the populations of many species varied as a function of distance from milled surfaces, caused, in part, by drainage. 4. Mosses had relatively high potential to immigrate to milled bogs because of their high fecundity and the wind-dispersal ability of their spores. The scarcity of mosses in abandoned milled bogs did not appear to be a result of the lack of immigrant propagules. Herbs had relatively low immigration potential, due to their rarity in edges, but herbs such as Eriophorum vaginatum were able to recolonize milled bogs in spite of this low potential. Shrub species generally had high immigration potential because of their abundance at edges and the high dispersal ability of propagules by wind, water and animals. Trees had high immigration potential due to their abundance at edges and their wind-dispersal abilities. 5. Synthesis and applications. An index of immigration potential provides information on the probable initial species pool after severe disturbance, against which the effects of local habitat suitability and establishment factors can be added to assess probable successional patterns. Its flexibility and applicability to varied life forms should make it useful for diagnosing recolonization bottlenecks in a wide variety of disturbance and restoration situations. It also allows for an assessment of the relative need for introducing species during the restoration of severely disturbed environments.

[1]  V. Salonen.  Relationship between the seed rain and the establishment of vegetation in two areas abandoned after peat harvesting , 1987 .

[2]  D. Greene,et al.  Secondary dispersal of tree seeds on snow , 1997 .

[3]  L. E. Anderson.  A Checklist of Sphagnum in North America North of Mexico , 1990 .

[4]  James A. Young,et al.  Seeds of woody plants in North America , 1993 .

[5]  C. B. McQueen.  Spatial pattern and gene flow distances in Sphagnum subtile , 1985 .

[6]  L. Rochefort,et al.  Wind erosion and surface stability in abandoned milled peatlands , 2002 .

[7]  L. Rochefort.  Sphagnum—A Keystone Genus in Habitat Restoration , 2000 .

[8]  S. Pimm,et al.  When does restoration succeed , 1999 .

[9]  F. Macnaeidhe,et al.  Weed invasion of milled‐over bog , 1986 .

[10]  J. Price,et al.  Energy and moisture considerations on cutover peatlands: surface microtopography, mulch cover and Sphagnum regeneration , 1998 .

[11]  C. Augspurger,et al.  MORPHOLOGY AND DISPERSAL POTENTIAL OF WIND‐DISPERSED DIASPORES OF NEOTROPICAL TREES , 1986 .

[12]  R. Moral,et al.  Early primary succession on the volcano Mount St. Helens , 1993 .

[13]  I. Noble,et al.  The use of vital attributes to predict successional changes in plant communities subject to recurrent disturbances , 1980, Vegetatio.

[14]  K. Walker,et al.  Restoration of species‐rich grassland on arable land: assessing the limiting processes using a multi‐site experiment , 2002 .

[15]  Peter H. A. Sneath,et al.  Numerical Taxonomy: The Principles and Practice of Numerical Classification , 1973 .

[16]  J. Laine,et al.  Long-Term Effects of Water Level Drawdown on the Vegetation of Drained Pine Mires in Southern Finland , 1995 .

[17]  R. E. Daniels,et al.  Handbook of European Sphagna , 1986 .

[18]  R. Longton,et al.  Deposition of moss spores in relation to distance from parent gametophytes , 1992 .

[19]  M. Mazerolle,et al.  Small-mammal responses to peat mining of southeastern Canadian bogs , 2001 .

[20]  Effets de lisière et d’isolement des habitats d’oiseaux chanteurs dans les tourbières exploitées , 2000 .

[21]  Joan G. Ehrenfeld,et al.  A Focus on Peatlands and Peat Mosses , 1988 .

[22]  V. Salonen.  Early plant succession in two abandoned cut-over peatland areas , 1990 .

[23]  A. Penttinen,et al.  Plant colonization of a bare peat surface: population changes and spatial patterns , 1992 .

[24]  L. E. Anderson,et al.  List of the Mosses of North America North of Mexico , 1990 .

[25]  H. Setälä,et al.  Plant colonization of bare peat surface ‐ relative importance of seed availability and soil , 1992 .

[26]  H. J. Scoggan.  The flora of Canada , 1978 .

[27]  R. P. Gemmell,et al.  The introduction of native plant species on industrial waste heaps: a test of immigration and other factors affecting primary succession , 1994 .

[28]  S. Sundberg.  The ecological significance of sexual reproduction in peat mosses (Sphagnum) , 2000 .

[29]  P. Poschlod,et al.  Experimental studies on the dispersal of plants and animals on sheep in calcareous grasslands , 1996 .

[30]  E. Johnson,et al.  Physical characterization of seed microsites--movement on the ground. , 1992 .

[31]  A. Desrochers,et al.  Conservation of bog plant species assemblages: Assessing the role of natural remnants in mined sites , 1999 .

[32]  C. Augspurger,et al.  Wind Dispersal of Artifical Fruits Varying in Mass, Area, and Morphology , 1987 .

[33]  H. Rydin,et al.  Spore number in Sphagnum and its dependence on spore and capsule size , 1998 .

[34]  P. H. Gregory,et al.  Microbiology of the Atmosphere , 1942, Nature.

[35]  G. Matlack.  Secondary dispersal of seed across snow in Betula lenta, a gap-colonizing tree species , 1989 .

[36]  George C. Hurtt,et al.  Reid's Paradox of Rapid Plant Migration Dispersal theory and interpretation of paleoecological records , 1998 .

[37]  Paul A. Keddy,et al.  Assembly and response rules: two goals for predictive community ecology , 1992 .

[38]  Ran Nathan,et al.  FIELD VALIDATION AND SENSITIVITY ANALYSIS OF A MECHANISTIC MODEL FOR TREE SEED DISPERSAL BY WIND , 2001 .

[39]  A. Desrochers,et al.  Avian recolonization of eastern Canadian bogs after peat mining , 1998 .

[40]  D. Greene,et al.  Wind Dispersal of Seeds from a Forest Into a Clearing , 1995 .

[41]  R. W. Kimmerer.  Reproductive Ecology of Tetraphis pellucida II. Differential Success of Sexual and Asexual Propagules , 1991 .

[42]  D. Vitt,et al.  Water and peat chemistry comparisons of natural and post-harvested peatlands across Canada and their relevance to peatland restoration , 1996 .

[43]  L. E. Anderson,et al.  Mosses of Eastern North America , 1982 .

[44]  Martin Zobel,et al.  Species pool: the concept, its determination and significance for community restoration. , 1998 .

[45]  A. Telenius,et al.  Experiments on adhesive dispersal by wood mouse: seed shadows and dispersal distances of 13 plant species from cultivated areas in southern Sweden , 1998 .